U.S. patent application number 10/181281 was filed with the patent office on 2003-07-10 for silicatic coating mass with improved stability.
Invention is credited to Heiberger, Franz, Schlaffer, Hermann.
Application Number | 20030127024 10/181281 |
Document ID | / |
Family ID | 7627832 |
Filed Date | 2003-07-10 |
United States Patent
Application |
20030127024 |
Kind Code |
A1 |
Heiberger, Franz ; et
al. |
July 10, 2003 |
Silicatic coating mass with improved stability
Abstract
The invention relates to a silicatic coating mass, a method for
producing the same, the use thereof and a substrate that is coated
with the silicatic coating mass. The silicatic coating mass
comprises water glass or a mixture of water glass and silica sol.
The molar ratio of SiO.sub.2 and alkali oxide is 5 to 30 mol
SiO.sub.2 per mol alkali oxide. Said coating mass also comprises
one or more organic ammonium compound/s, one or more filler/s and
optionally other additives. The inventive silicatic coating mass is
provided with increased shelf live when consisting of one component
and the coated substrate is characterised by an increased stability
against atmospheric influences.
Inventors: |
Heiberger, Franz; (Augsburg,
DE) ; Schlaffer, Hermann; (Neusass, DE) |
Correspondence
Address: |
Leopold Presser
Scully Scott Murphy & Presser
400 Garden City Plaza
Garden City
NY
11530
US
|
Family ID: |
7627832 |
Appl. No.: |
10/181281 |
Filed: |
November 13, 2002 |
PCT Filed: |
January 18, 2001 |
PCT NO: |
PCT/EP01/00548 |
Current U.S.
Class: |
106/634 ;
428/703 |
Current CPC
Class: |
C04B 28/24 20130101;
C04B 2111/00482 20130101; C04B 12/04 20130101; C04B 28/26 20130101;
C04B 28/24 20130101; C04B 2103/0005 20130101; C04B 24/2641
20130101; C04B 2103/0005 20130101; C04B 12/04 20130101; C04B
24/2641 20130101; C04B 28/26 20130101; C09D 1/04 20130101 |
Class at
Publication: |
106/634 ;
428/703 |
International
Class: |
C04B 012/04 |
Foreign Application Data
Date |
Code |
Application Number |
Jan 18, 2000 |
DE |
10001831.9 |
Claims
1. A silicatic coating mass comprising water glass or a mixture of
water glass and silica sol having a molar ratio of SiO.sub.2 to
alkali oxide of 5 to 30 mol SiO.sub.2 per mol alkali oxide, one or
more organic ammonium compound(s), and one or more filler(s).
2. A silicatic coating mass according to claim 1, characterized in
that the molar ratio of SiO.sub.2 to alkali oxide is 10 to 25 mol
SiO.sub.2 per mol alkali oxide.
3. A silicatic coating mass according to claim 2, characterized in
that the molar ratio of SiO.sub.2 to alkali oxide is 15 to 25 mol
SiO.sub.2 per mol alkali oxide.
4. A silicatic coating mass according to one or more of the
preceding claims, characterized in that the alkali oxide is
potassium oxide.
5. A silicatic coating mass according to one or more of the
preceding claims, characterized in that the silica sol has an
average particle size of <10 nm.
6. A silicatic coating mass according to one or more of the
preceding claims, characterized in that the organic ammonium
compound(s) has (have) the following formula
(I):+NR.sup.1R.sup.2R.sup.3R.sup.4 X.sup.- (I)with R.sup.1, R.sup.2
and R.sup.3 each being independently an alkyl group having 1 to 20
carbon atoms, which may optionally be substituted by a functional
group, an aryl group having 6 to 20 carbon atoms, which may
optionally be substituted by a functional group, or hydrogen, and
with R.sup.4 being an alkyl having 1 to 20 carbon atoms, which may
otionally be substituted by a functional group, an aryl group
having 6 to 20 carbon atoms, which may optionally be substituted by
a functional group, hydrogen or
--(CH.sub.2)x--N.sup.+R.sup.5R.sup.6R.sup.7Y.sup.-, with R.sup.5,
R.sup.6 and R.sup.7 each being independently an alkyl group having
1 to 20 carbon atoms, which may optionally be substituted by a
functional group, an aryl group having 6 to 20 carbon atoms, which
may optionally be substituted by a functional group, or hydrogen,
and wherein at least one of R.sub.1,R.sup.2, R.sup.3 and R.sup.4 is
not hydrogen, x is an integer between 1 and 10, and X.sup.- and
Y.sup.- each may be the same or different and are anions.
7. A silicatic coating mass according to claim 6, characterized in
that the organic ammonium compound is a compound of the following
formula (II): 2with R.sup.1, R.sup.2, R.sup.5 and R.sup.7 each
being independently an alkyl group having 1 to 20 carbon atoms, an
aryl group having 6 to 20 carbon atoms, or hydrogen. R.sup.3 and
R.sup.6 each are independently a hydroxy-substituted alkyl group
having 1 to 6 carbon atoms, x is an integer between 1 and 6, and
X.sup.- and Y.sup.- may be the same or different and are in each
case an anion.
8. A silicatic coating mass according to claim 7, characterized in
that R.sup.1, R.sup.2, R.sup.5 and R.sup.7 each are a methyl group,
R.sup.3 and R.sup.6 each are a 2-hydroxypropyl group, x=6 and
X.sup.- and Y.sup.- each are OH.sup.-.
9. A silicatic coating mass according to one or more of the
preceding claims, characterized in that it further comprises a
polymer.
10. A silicatic coating mass according to claim 9, characterized in
that the polymer is a (meth)acrylate homopolymer or a
(meth)acrylate copolymer.
11. A method for producing a silicatic coating mass according to
one or more of claims 1 to 10, characterized in that the water
glass, or the mixture of water glass and silica sol having a ratio
of 5 to 30 mol SiO.sub.2 per mol alkali oxide, and the organic
ammonium compound(s) are mixed, the filler(s) and optionally
further additives are added prior to, or after, the mixing of the
water glass, or the mixture of water glass and silica sol, with the
organic ammonium compound(s), and water may optionally be added to
render the mass ready-for-use.
12. A use of a silicatic coating mass according to one or more of
claims 1 to 10 for coating substrates.
13. A coated substrate obtainable by the application of the
silicatic coating mass according to one or more of claims 1 to 10
on a substrate and subsequent silicification.
Description
[0001] The invention relates to a silicatic coating mass, a method
for producing the same, the use thereof and a substrate coated with
the silicatic coating mass.
[0002] Silicatic coating masses find use in a plurality of
technical applications. These include the application of protective
coatings on mineral substrates such as lime and lime cement
plasters and concrete, on synthetic materials such as PVC and on
metallic surfaces made of iron or non-ferric metals. The silicatic
coating masses include, in particular, the purely inorganic
silicate paints as well as dispersion silicate paints that may
contain up to 5% by weight of inorganic moieties under DIN 18
363.
[0003] These silicatic coating masses are formulated in practice
with pigments, fillers, water and water glass as the binding agent.
Water glass is understood to be melts of alkali silicates, which
are solidified in a glass-like fashion, and aqueous solutions
thereof which are obtainable from alkali carbonates and SiO.sub.2.
The water glass binding agent causes the special properties of
silicatic coating masses. The coating composition is silicified due
to the evaporation of water and the reaction with carbon dioxide,
i.e. the binding agent is converted into a water-insoluble
silicatic network which may optionally include the components of
the undercoat. Thereby, a very hard coating with high gas
permeability is formed. The water glass used is generally produced
by melting together quartz sand and alkali carbonate. As a rule,
the molar ratios of SiO.sub.2 to alkali oxide, the two main
components of water glass, are set to not more than 4.
[0004] Coatings obtained from silicatic coating masses and which
use a water glass binding agent have, however, the disadvantage
that they tend to wash out alkali when acted upon by water, which
may result in bright streaks, reduced bonding to the undercoat and
thus chalking, i.e. an easy wiping off of particles. In particular
in the case of chemical stress, such as acidic rain, or climatic
stress, such as alternating frost and thaw, these coatings have
proved to be of insufficient stability.
[0005] Increased stability with respect to such stress was found
for silicatic coatings containing water glass with a higher molar
ratio of SiO.sub.2 to alkali oxide. However, it has not been
possible to produce a coating mass for such coatings which is
stable in storage since silicatic coating masses containing water
glass at a molar ratio of SiO.sub.2 to alkali oxide of >4 are
not stable. The higher the SiO.sub.2 content is, the more easily
occurs gel formation, and thus solidification of the water glass.
This problem was circumvented by providing two- or multi-component
systems whose components could only be mixed directly prior to use.
WO 95/29139 describes a silicate mass which comprises a water glass
binding agent with a molar ratio of silica to alkali oxide of 4 to
25 and which further contains oxides from the group consisting of
alumina, calcium oxide, titanium dioxide, magnesium oxide,
zirconium oxide and/or boron oxide. However, such a silicate mass
has a high reactivity and is therefore exclusively described as a
multi-component system with a very short pot life in the mixed,
one-component state. This is disadvantageous in particular for use
in the field of paint coats since the components can only be mixed
directly prior to use and must then be rapidly processed.
[0006] Consequently, the invention is based on the object of
providing a silicatic coating mass with a high molar ratio of
silica to alkali oxide, which is also stable in the one-component
state and is suitable for the field of paint coats.
[0007] This object was surprisingly attained by a silicatic coating
mass comprising water glass or a mixture of water glass and silica
sol with a molar ratio of SiO.sub.2 to alkali oxide of 5 to 30 mol
SiO.sub.2 per mol alkali oxide, one or more organic ammonium
compound(s) and one or more filler(s).
[0008] A silicatic coating mass containing water glass or a mixture
of water glass and silica sol with a molar ratio of SiO.sub.2 to
alkali oxide of 5 to 30 mol SiO.sub.2 per mol of alkali oxide, and
one or more organic ammonium compound(s), exhibits high storage
stability in the ready-to-use, one-component state. As a rule, it
has a storage stability of at least 6 months.
[0009] Preferably the molar ratio of SiO.sub.2 to alkali oxide in
the water glass, or in the mixture of water glass and silica sol,
ranges from 10 to 25 mol SiO.sub.2 per mol alkali oxide, more
preferably from 15 to 26 mol SiO.sub.2 per mol alkali oxide.
[0010] The alkali oxide of the water glass of the silicatic coating
mass in accordance with the invention preferably is potassium
oxide. Potassium oxide is preferred since, as compared to sodium
oxide, it tends less to blooming and is less expensive than lithium
oxide. The alkali oxide is preferably contained in an amount of
from 0.5 to 3% by weight, more preferably of from 0.5 to 0.8% by
weight, based on the total weight of the silicatic coating mass.
Especially preferred is a content of alkali oxide of 0.5% by
weight.
[0011] The reference to alkali oxides corresponds to the current
practice in silicate analysis of indicating metal contents as
oxides, even if these are actually present in the form of chemical
compounds such as silicates or the like.
[0012] Silica sol is understood to be aqueous solutions of
colloidal silicic acid. Preferably an alkaline silica sol is used.
A solids content of 10 to 50% is also preferred.
[0013] Advantageously, the silica sol has moreover a mean particle
size of <10 nm. The silica sols used according to the invention
are, in addition, preferably characterized by a very uniform and
fine distribution spectrum.
[0014] The silica gel may be present in a moiety of from 3 to 30%
by weight, based on the total weight of the silicatic coating
mass.
[0015] The water glass having a molar ratio of SiO.sub.2 to alkali
oxide of 5 to 30 mol SiO.sub.2 per mol alkali oxide, or the mixture
of water glass and silica sol, which is characterized by a molar
ratio of SiO.sub.2 to alkali oxide of 5 to 30 mol SiO.sub.2 per mol
alkali oxide, acts as a binding agent in the silicatic coating mass
according to the invention.
[0016] The water glass, or the mixture of water glass and silica
sol, having a molar ratio of SiO.sub.2 to alkali oxide of 5 to 30
mol SiO.sub.2 per mol alkali oxide is preferably contained in the
silicatic coating mass according to the invention in an amount of
from 3 to 40% by weight, more preferably of from 15 to 35% by
weight, based on the total weight of the silicatic coating
composition.
[0017] The organic ammonium compound(s) in the silicatic coating
mass according to the invention preferably has (have) the following
formula (I):
+NR.sup.1R.sup.2R.sup.3R.sup.4 X.sup.- (I)
[0018] with R.sup.1, R.sup.2 and R.sup.3 each being independently
an alkyl group having 1 to 20 carbon atoms, which may optionally be
substituted by a functional group, an aryl group having 6 to 20
carbon atoms, which may optionally be substituted by a functional
group, or hydrogen, and with R.sup.4 being an alkyl group having 1
to 20 carbon atoms, which may optionally be substituted by a
functional group, an aryl group having 6 to 20 carbon atoms, which
may optionally be substituted by a functional group, hydrogen or
--(CH.sub.2).sub.x--N.sup.+R.sup.5R.sup.6R.sup.7Y.sup.- -, with
R.sup.5, R.sup.6 and R.sup.7 each being independently an alkyl
group having 1 to 20 carbon atoms, which may optionally be
substituted by a functional group, an aryl group having 6 to 20
carbon atoms, which may optionally be substituted by a functional
group, or hydrogen, wherein at least one of R.sup.1, R.sup.2,
R.sup.3 and R.sup.4 is not hydrogen, x is an integer between 1 and
10, and X.sup.- and Y.sup.- each may be the same or different and
are anions. The functional group can be e.g. a hydroxy group, an
amino group, an amino alkyl group having 1 to 6 carbon atoms, a
thiol group or an alkoxy group having 1 to 6 carbon atoms,
preferably a hydroxy group. The anion can be freely selected in as
far as it does not reduce the effect of the organic ammonium
compound; thus, the anion may be F.sup.-, Cl.sup.-, Br.sup.-,
I.sup.- or OH.sup.-, for example.
[0019] Especially preferred is an organic ammonium compound of the
formula (II): 1
[0020] with R.sup.1, R.sup.2, R.sup.5 and R.sup.7 each being
independently an alkyl group having 1 to 20 carbon atoms, an aryl
group having 6 to 20 carbon atoms, or hydrogen. R.sup.3 and R.sup.6
each are independently a hydroxy-substituted alkyl group having 1
to 6 carbon atoms, x is an integer between 1 and 6, and X.sup.- and
Y.sup.- may be the same or different and are in each case an anion,
e.g. F.sup.-, Cl.sup.-, Br.sup.-, I.sup.- or OH.sup.-.
[0021] Preferably the alkyl groups of the formulae (I) or (II)
contain 1 to 6 carbon atoms, and selected examples are methyl,
ethyl, propyl, isopropyl, n-butyl, tert-butyl, pentyl, hexyl and
cyclohexyl. Selected examples of a hydroxy-substituted alkyl group
having 1 to 6 carbon atoms are hydroxymethyl, hydroxyethyl,
1-hydroxypropyl and 2-hydroxypropyl.
[0022] Especially preferred is an organic ammonium compound, in
which R.sup.1, R.sup.2, R.sup.5 and R.sup.7 each are a methyl
group, R.sup.3 and R.sup.6 each are a 2-hydroxypropyl group, x=6
and X.sup.- and Y.sup.- each are OH.sup.-.
[0023] The content of the organic ammonium compound(s) in the
silicatic coating mass ranges preferably from 0.1 to 3% by weight,
likewise preferably from 1 to 3% by weight and more preferably from
1.5 to 3% by weight, based on the total weight of the coating
composition.
[0024] The silicatic coating mass according to the invention
comprises one or more fillers, their content ranging preferably
from 10 to 45% by weight, based on the total weight of the
silicatic coating mass. Quartziferous fillers, calcitic fillets,
layer silicates and/or feldspar can e.g. be used as fillers.
[0025] The silicatic coating mass according to the invention may
further contain a polymer. Polymer-containing silicatic coating
masses are, in particular, used as dispersion silicate paints. The
addition of a polymer results in higher flexibility of the coating
obtained after silicification, which is advantageous, in
particular, on natural substrates and polymer substrates. In
accordance with DIN regulation 18 363, paragraph 2.4.1, dispersion
silicate paints may contain at the most 5% organic moieties.
Irrespective of this DIN regulation, however, a polymer content of
up to 15% by weight, based on the total weight of the silicatic
coating mass, in particular of from 1 to 15% by weight, is
advantageous. Especially preferred is a polymer content of from 3
to 10% by weight. As a rule, the polymer is incorporated into the
silicatic coating mass in the form of a dispersion. The solids
content of the polymer dispersion is preferably from 20 to 60% by
weight. Preferably the polymer is a (meth)acrylate homopolymer or a
(meth)acrylate copolymer. A butyacrylate-methylmethacrylate
copolymer or a styrene-acrylate copolymer is especially
preferred.
[0026] Furthermore, the silicatic coating mass may comprise oxides
from the group consisting of alumina, calcium oxide, titanium
dioxide, magnesium oxide, zirconium oxide and/or boron oxide.
[0027] Moreover, for adaptation to a desired color, pigments may be
contained in the silicatic coating mass. Mineral oxides, in
particular oxides having a rutile or spinel structure, such as e.g.
iron oxides, are used to advantage. The pigments are preferably
contained in the silicatic coating mass in an amount of from 5 to
50% by weight.
[0028] Moreover, the silicatic coating mass may contain e.g.
thickeners, hydrophobing agents, dispersing agents and/or defoaming
agents as additives.
[0029] Examples of thickening agents are polysaccharides, cellulose
ether and bentonite. Their content may amount to 0.1 to 5% by
weight, based on the total weight of the silicatic coating
mass.
[0030] The hydrophobing agent may comprise, for example,
polysiloxanes and, in particular, amino-functional polysiloxanes.
The hydrophobing agent may be present in an amount of from 0.1 to
5% by weight, based on the total weight of the silicatic coating
mass.
[0031] The dispersing agents used may be, for instance, sodium and
potassium polyacrylates. The dispersing agent is preferably present
in an amount of from 0.1 to 0.5% by weight, based on the total
weight of the silicatic coating mass.
[0032] Mineral and/or silicone oils may be present in the silicatic
coating mass as defoaming agents. Preferably the amount of the
defoaming agent present ranges from 0.1 to 1% by weight, based on
the total weight of the silicatic coating mass.
[0033] Moreover, the silicatic coating mass may contain water,
preferably in an amount of from 15 to 50% by weight, based on the
total weight of the silicatic coating composition.
[0034] Although the advantages of the invention are especially
evident in a one-component silicatic coating mass, the splitting-up
of the silicatic coating mass into two components is also possible.
In this case, one component preferably contains the filler and
optionally further additives, such as pigments, and the second
component contains the water glass or the mixture of water glass
and silica sol having a molar ratio of SiO.sub.2 to alkali oxide of
5 to 30 mol SiO.sub.2 per mol alkali oxide, and the organic
ammonium compound.
[0035] The silicatic coating mass according to the invention can be
produced by mixing the water glass, or the mixture of water glass
and silica sol, having a ratio of SiO.sub.2 to alkali oxide of 5 to
30 mol SiO.sub.2 per mol alkali oxide, with one or several organic
ammonium compound(s), wherein the filler(s) and optionally further
additives, such as pigments, are added prior to, or after, the
mixing of the water glass, or the mixture of water glass and silica
sol, with the organic ammonium compound. If a polymer is added to
the silicatic coating mass, it is preferably added in-the form of a
polymer dispersion prior to the mixing of the water glass, or the
mixture of water glass and silica sol, with the organic ammonium
compound.
[0036] Further variants for the production of the silicatic coating
mass will now be presented.
[0037] The silicatic coating mass according to the invention can be
produced by initially dispersing the filler(s) and optionally the
pigments in water, and then adding the organic ammonium compound(s)
and thereafter optionally the polymer in the form of a dispersion.
After thorough dispersing, the water glass, or the mixture of water
glass and silica sol, and then optionally further additives, e.g.
thickeners and/or hydrophobing agents, are added. A dispersion that
is as homogeneous as possible is obtained by further stirring.
[0038] Alternatively, the silicatic coating mass according to the
invention can be produced as follows:
[0039] At first, the water glass, or the mixture of water glass and
silica sol, is mixed with the organic ammonium compound(s).
Pigments may optionally be added thereto. Subsequently, the
filler(s) and optionally a polymer dispersion are stirred into the
mixture. Finally, further additives, such as a thickener and/or a
hydrophobing agent, may optionally be added.
[0040] The silicatic coating mass according to the invention can be
used for coating. substrates.
[0041] Advantageously, the silicatic coating mass in accordance
with the invention can be used for protecting substrates against
atmospheric influences.
[0042] The silicatic coating mass is suitable for all applications
for which silicate paints and/or dispersion silicate paints have
hitherto been used. These also include, in addition to protective
coatings against atmospheric influences, coatings for decorative
purposes or ornaments.
[0043] The invention also includes substrates which are coated with
the silicatic coating mass according to the invention. Coated
substrates can be obtained by applying the silicatic coating mass
according to the invention onto a substrate, e.g. by means of
dipping, spreading, rolling, pouring or spraying, with subsequent
silicification taking place.
[0044] The substrates onto which the silicatic coating mass
according to the invention can be applied are preferably mineral
substrates, metallic substrates, natural substrates or plastic
substrates.
[0045] Special examples of mineral substrates include mortar (cf.
e.g. DIN 18555), plasters, e.g. lime and cement plasters, concrete,
natural stone, e.g. lime sandstone, and brickwork.
[0046] Metallic substrates are e.g. zinc-plated surfaces or
aluminum substrates.
[0047] For instance, cellulose-containing materials (e.g. paper,
cardboard, wood, wood-containing materials such as chipboards),
biologically degradable polymers (e.g. protein- or
starch-containing materials) and textile materials (e.g. cotton,
linen) are understood by natural substrates.
[0048] Wood and wood-containing materials are especially preferred
cellulose-containing materials.
[0049] Plastic substrates can be, for example, poly(meth)acrylates,
polycarbonates, polystyrenes, polyethylene glycols and/or PVC.
[0050] Substrates also include substrates provided with a priming.
A priming may serve e.g. to improve adhesion between the non-primed
substrate and the silicatic coating mass and/or the coating
obtained by means of application and silicification. Examples of
primings, onto which the silicatic coating mass can be applied for.
producing a coated substrate, include e.g. primings on the basis of
polyorganosiloxanes which may optionally be modified.
[0051] Coated substrates according to the invention excel by the
advantages offered by high water resistance, adhesion and abrasion
resistance. These advantages result from the reduction and/or
absence of washing-out of alkali so that the coating remains in its
original state, i.e. the state at the time when silicification is
concluded. The formation of bright streaks (chalking), an increase
in porosity and an associated reduced bonding of the coating to the
substrate (erosion of the coating) is considerably delayed or
prevented.
[0052] The advantageous properties of the coating mass according to
the invention, or of the coated substrates according to the
invention, can be proved by means of the following test
procedures.
[0053] 1. Method for Testing Water Resistance (Early Water
Resistance):
[0054] Two coatings of the silicatic coating mass to be tested are
successively knife-coated onto fiber-reinforced cement plates (e.g.
Eterplan). The first coating is applied with a width of 80 mm and a
length of 430 mm, and the second coating is applied with a width of
60 mm and a length of also 430 mm. The time interval between the
coatings is at least 12 hours, the radial screw clearance of the
doctor blade is 225 .mu.m. The fiber-reinforced cement plates, the
coating composition and the coated plates are stored under standard
atmospheric conditions (23.degree. C., 50% relative humidity). Four
hours after applying the second coating, 50 ml of completely
demineralized water are dripped onto the surface of the coating by
means of a burette. The burette is adjusted in such a manner that
the 50 ml water are dripped onto the surface within 10 minutes. The
sample surface is disposed at an angle of 135.degree. to the
burette. After completely drying the surface, i.e. as a rule after
24 hours, the samples are examined. The following distinction is
made depending on the intensity of the curtaining marks:
1 Class 0: no curtaining visible Class 1: visible curtaining Class
2: extremely visible curtaining Class 3: the paint coat is washed
out.
[0055] 2. Method for Testing Adhesion (Adhesive Tensile Strength)
(According to DIN 18 555 Part 6):
[0056] The silicatic coating mass is applied onto concrete plates
of the strength class B 55 according to DIN 1045, which have a
tear-off strength of at least 3 N/mm.sup.2. The finished samples
are stored for at least 14 days under standard atmospheric
conditions (23.degree. C., 50% relative humidity). The measurement
of the adhesive tensile strength is carried out in accordance with
DIN 18 555, Part 6, item 5 at a rate of loading of 100 N/s.
[0057] 3. Method for Testing Abrasion Resistance (Washing and Scrub
Resistance) (According to DIN 53 778, Part 2);
[0058] Deviating from the DIN standard, the following substrates
are used and the coating is produced as described below. Two
coatings of the coating composition are successively knife-coated
onto fiber-reinforced cement plates (e.g. Eterplan).
[0059] The first coating is applied with a width of 80 mm and a
length of 430 mm, and the second coating is applied with a width of
60 mm and a length of also 430 mm. The time interval between the
coatings should be at least 12 hours, the radial screw clearance of
the doctor blade is 225 .mu.m. The fiber-reinforced cement plates,
the coating composition and the coated substrates are stored under
standard atmospheric conditions (23.degree. C., 50% relative
humidity). Further testing occurs in accordance with DIN 53 778,
Part 2.
[0060] As regards spreadability and sprayability, the silicate
coating masses according to the invention did not show any
recognizable difference during a 6-month storage period to the
dispersion silicate paints known up until now.
[0061] The coated substrates obtained by means of the application
and silicification of the coating masses according to the invention
are characterized by high stability against chemical influences,
such as acidic rain, and atmospheric influences, such as
alternating frost and thaw.
[0062] The invention will now be explained in more detail in the
following by means of the examples.
EXAMPLE 1
[0063] A mixture of 3.8% by weight of a 30% potash water glass
solution and 17% by weight of a silica sol having a particle size
of 9 nm and a solids content of 20%, which mixture has a molar
ratio of SiO.sub.2 to potassium oxide of 10 mol SiO.sub.2 per mol
potassium oxide, is mixed with 1.5% by weight of (CH.sub.3).sub.3
[CH.sub.3CH (OH) CH.sub.2]N.sup.+--(CH.sub.2)
.sub.6--.sup.+N(CH.sub.3).sub.2 [CH.sub.2CH(OH)
CH.sub.3]OH.sup.-OH.sup.- (N,N'-di(2-hydroxypropyl)--N,N'-
-tetramethyl hexylene diamine, 20% aqueous solution). After the
addition of 10.5% by weight of iron oxide, stirring is carried out
for 5 minutes. Subsequently, 29.3% by weight of layer silicate
mixture (kaolinite, chlorite, muscovite) and 6.0% by weight of
butyl methacrylate/methyl methacrylate copolymer (as a 50%
dispersion) are added by means of stirring so that a homogenous
dispersion is formed. After the addition of 0.2% by weight of
bentonite, 0.1% by weight of xanthane and 1.5% by weight of an
aqueous amino-functional polydimethyl siloxane emulsion (solids
content 50%) (Wacker BS 1306), the mass is rendered ready for use
by adding 30.1% by weight of water. The silicatic coating mass
obtained is used for coating a concrete substrate.
[0064] The coated substrate is characterized by an early water
resistance of Class 0, an adhesive tensile strength of 3 to 4
N/mm.sup.2 and a washing and scrub resistance of >10,000
cycles.
EXAMPLE 2
[0065] 35% by weight of an 18% potash water glass solution with a
molar ratio of SiO.sub.2 to potassium oxide of 6 are mixed with
0.5% by weight of N,N'-di(2-hydroxypropyl)-N,N'-tetramethyl
hexylene diamine (20% aqueous solution). 13.95% by weight of
potassium aluminum silicate, 9% by weight of calcium carbonate, 8%
by weight of dehydrated aluminum silicate hydrate, 4% by weight of
calcium fluoride and 0.4% by weight of silica as fillers, and 7.5%
by weight of an aqueous dispersion of a methyl methacrylate butyl
acrylate copolymer (solids content 50%) are added by stirring so
that a homogeneous dispersion is formed. After the addition of 1%
by weight of an aqueous aminoalkyl polydimethyl siloxane emulsion
(solids content 50%) (Wacker BS 1306), 0.25% by weight of
tetrasodium-N-(1,2-dicarboxyethyl)-N-alkyl sulfosuccinamide, 0.2%
by weight of a mixture of hydrophobic silicic acid, liquid
hydrocarbons, non-ionogenic emulsifiers and synthetic copolymers
(Agitan 281), 0.125% by weight of xanthane and 0.1% by weight of
sodium carboxymethyl cellulose, the mass is rendered ready for use
by adding 19.975% by weight of water. The silicatic coating mass
obtained is used for coating a mineral substrate (lime cement
plaster).
EXAMPLE 3
[0066] 22% by weight of a filler (intergrowth of chloride, quartz
and mica) are dispersed in 28.6% by weight of water. 2% by weight
of (N,N'-di(2-hydroxypropyl)-N,N'-tetramethyl hexylene diamine (20%
aqueous solution) are added. Subsequently, 9% by weight of an
aqueous dispersion of a butyl acrylate/methyl methacrylate
copolymer (solids content 50%) are added. A mixture of 20% by
weight of silica sol (particle size 7 to 8 nm, solids content 30%)
and 6% by weight of a 21% potash water glass solution (molar ratio
of SiO.sub.2 to potassium oxide=10) are added by stirring. After
dispersing said components, 10% by weight of a polysaccharide
solution (solids content 5%) are added 0.2% by weight of an aqueous
emulsion of an aminoalkyl-substituted polydimethyl siloxane (Wacker
BS 1306) (solids content 50%), 0.2% by weight of
tetrasodium-N-(1,2-dicarboxyethyl)-N-alkyl sulfosuccinamide and
0.2% by weight of a mixture of hydrophobic silicic acid, liquid
hydrocarbons, non-ionogenic emulsifiers and synthetic copolymers
(Agitan 281) are added as further additives and stirred until a
dispersion, which is as homogeneous as possible, is obtained. The
prepared silicatic coating mass is used for coating a natural stone
substrate (sandstone).
EXAMPLE 4
[0067] Initially, 19% by weight of an aqueous dispersion of a
(meth)acrylic acid copolymer (solids content 50%) are prepared. A
mixture of 6% by weight of a 21% potash water glass solution and
10% by weight of silica sol (solids content 30%, average particle
size 7 to 8 nm) (molar ratio of SiO.sub.2 to potassium oxide=10)
are mixed with 1% by weight of
N',N-di(2-hydroxypropyl)-N,N'-tetramethyl hexylene diamine and
added to the copolymer dispersion. Subsequently, 22% by weight of a
filler (intergrowth of chloride, quartz and mica), 10% by weight of
a 5% polysaccharide solution, 2% by weight of an aqueous emulsion
of an amino-alkyl-group-containing polydimethyl siloxane (Wacker BS
1306) (solids content 50%), 0.2% by weight of
tetrasodium-N-(1,2-dicarboxyethyl- )-N-alkyl sulfosuccinamide and
0.2% by weight of a mixture of hydrophobic silicic acid, liquid
hydrocarbons, non-ionogenic emulsifiers and synthetic copolymers
(Agitan 281) are added and filled with 29.6% by weight of water.
The obtained silicatic coating mass is used for coating a mixed
undercoat containing organic fibers (wood-fiber-reinforced cement
substrate).
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